Bittersweet Chocolate Irish Whiskey Cake

Preparation

1. Step 1

   Position rack in center of oven and preheat to 350°F. Butter and flour 8-inch-diameter springform pan.

   Step 2

   Boil 1/2 cup whiskey in small saucepan until reduced to 1/4 cup, about 2 minutes. Combine bittersweet chocolate, espresso powder mixture, and 1/4 cup boiled whiskey in small metal bowl. Place bowl over saucepan of simmering water; stir until mixture is smooth. Remove bowl from over water. Finely grind almonds with 2 tablespoons flour in processor.

   Step 3

   Using electric mixer, beat 1/2 cup butter and 6 tablespoons vanilla sugar in medium bowl until fluffy. Beat in egg yolks 1 at a time, then sea salt. Fold in chocolate mixture, then ground almond mixture. Using clean dry beaters, beat egg whites in another bowl until soft peaks form. Gradually add 1 tablespoon vanilla sugar, beating until stiff peaks form. Fold whites into batter alternately with remaining 4 tablespoons flour in 3 additions. Transfer batter to prepared pan.

   Step 4

   Bake cake until tester inserted into center comes out clean, about 40 minutes. Cool in pan on rack 30 minutes. Remove pan sides and cool cake completely.

   Step 5

   Combine semisweet chocolate and remaining 2 tablespoons whiskey in small metal bowl. Place bowl over saucepan of simmering water and stir until smooth. Remove bowl from over water. Add remaining 1/4 cup butter to chocolate mixture, 1 small piece at a time, whisking until each piece is melted before adding next. Place bowl over larger bowl of ice water. Using electric mixer, beat icing until thickened to spreadable consistency, about 1 minute. Spread icing over top and sides of cake. DO AHEAD Can be made 8 hours ahead. Cover with cake dome and let stand at room temperature.